There are many applications for fiber-optic pigtailed collimators and similar components within optical systems and assemblies. A fiber-optic collimator delivers light through an optical fiber or similar pigtail or conduit. The optical fiber or other conduit couples directly to a light source, or other devices capture the light from the light source and deliver the light to the optical fiber. The light transmits through the optical fiber to the end-face of the fiber, fixed in a ferrule, where the light launches into free space as a diverging beam. The light is then incident onto a lens, which converges or collimates the beam with a lower divergence angle for further propagation along a defined optical axis.
There are also many applications for polarizers within optical systems and components. Specifically, many systems or components utilize polarizers where it is important to control or analyze the direction and intensity of polarized light or light oriented in a specific polarization state. In these uses and applications, once the light is polarized, there is a need to analyze and determine the orientation of the polarized light. The use of polarizers combined with analyzers of polarized light most generally is referred to as a polarization diversity scheme or system. In many polarization diversity schemes or systems, fiber-optic collimators provide the input and exit of light.
Optical systems that efficiently embody a polarization diversity scheme generally include at least the following features: (1) a fiber-optic input and/or exit of light, (2) collimation and/or focusing of the light, or other beam-shaping, (3) polarization selection, manipulation, and/or analysis of the light, and if necessary, (4) a fiducial mark or tag indicating polarization and/or analysis direction or manipulation of the light. These features are conventionally achieved by functional optical elements located distinctly and separately in a free-space set-up, breadboard, or assembly.
A major problem in the art of optical systems that use polarization diversity schemes, systems, and techniques is that the optical or fiber-optic components and the polarization components, such as polarizers and analyzers, are distinct. The use of distinct, or separate, or uniquely specified optical or fiber-optic components when combined with polarizing or analyzing components leads to optical systems with multiple distinct components, which can be exceedingly numerous. Polarization diversity schemes provided by such systems with multiple components are complex and cumbersome. Thus, optical or fiber-optic systems that incorporate polarization diversity schemes exhibit exorbitant cost in terms of the use of bulk components, the number and size of components, and a large unwieldy packaging footprint, as well as size and weight that are ill suited for many applications. Further, a solution using separate optical elements exposes each of the separate optical surfaces to environmental exposure.
Optical collimators that use a polarization maintaining pigtail also have disadvantages. Polarization maintaining (PM) fibers have ellipticity in the polarization profile as defined by the stress inducing core guiding elements of the fiber. PM fibers are also typically single mode, making it difficult to inject or couple light into the fiber and suffer high sensitivity to bend loss. PM fiber is also complex to manufacture, high cost, and fragile compared to the use of standard single or multimode fiber.
The present technology is directed to overcoming these and other deficiencies in the art.